Pneumatic-despatch-tube apparatus.



C. P. HIDDEN.

PNEUMATIC DESPATCH TUBE APPARATUS.

7 APPLICATION FILED NOV. 23. 1912. 1,154,570. PatentedSept. 21, 1915.

2 SHEETS-SHEET 1.

WITNESSES:

MW INVENTOR. M @213 Z r/J/WAMW COLUMBIA PLANOORAPH C0,, WASHINGTON, D.c.

c. P. HIDDEN.

PNEUMATIC DESPATCH TUBE APPARATUS.

APPLICATION FILED NOV. 23. 1912.

Patented Sept. 21, 1915.

2 SHEETS-SHEET Z.

INVENTOR.

COLUMBIA PLANOORAPH C0,, WASHINGTON. D. c.

ticularly set forth in the r srars Parisian @FFTQE.

CHARLES P. HIDDEN, OF WINCHESTER, MASSACHUSETTS, ASSIGNOB TO THELAIVISON COMPANY, 035 BOSTON, MASSACHUSETTS, A CGRPOBATION OF NENJERSEY.

PNEUMATIC-DESPATGH-TUBE APP ARATUS.

Specification of Letters Patent.

Patented se t. 21, 1915-.

Application filed Hot/ember 23, 1912. Serial No. 733,078.

and Commonwealth of Massachusetts, have I invented certain new anduseful Improvements in Pneumatie-Despatch-Tube Apparatus, of'which thefollowing is a specification. I

This invention relates to pneumatic despat'ch tube apparatus and has forone of its objects the provision of improved timing means in despatchsystems operating at pressures above atmospheric- Timing mechanisms suchas those described by G. H. Woodman in his Patent No. 649,094, dated MayS, 1900, have been found to be of great value in practice and efiect amaterial saving of power in operating system of the type in question.The more accurately the timing mechanism can be adjusted to meet theconditions encountered in practice, the less the margin of time, overthat actually consumed in transmitting a carrier throughthe system adetermined distance, need to be allowedto assure the practicallyinvariable delivery of the carrier; and the less this margin, the lessthe waste of power consumed in driving air uselessly through thetransmission tube.

. In compression systems the pressure used may in some instancesberelatively high and it would hence be desirable if a limiting pressurecould be provided where air. for ,eX- ample, must seep throughrestricted or filamentary conduits or passages in order to provide aworking period of proper duration. The provision of such a limitingpressure is contemplated in the herein described invention and tends torender the time element mechanism more equable in its action, regardlessof the pressure used in the system, and also tends toreduce the tendencyfor the minute venting perforations or passages therein to becomeclogged by dustentrained in the air currents traversing the same.

These and other objects of my invention will be hereinafter referredtoand the novel elements and combination of elements where by they may beattained will be more parclaims appended hereto.

In the accompanying drawings. which form a part hereof and in which likereference characters designate like parts throughout the several views,Thave exemplified two preferred constructions; but I am aware thatvarious modifications and changes may be made herein without departingfrom the spirit of my invention, and I hence desire to be limited onlyby the scope of said claims. I

Referring to the drawings: Figure 1 is a vertical transverse mediansection of a terminal equipped with my improved timing mechanism. Fi 2is a similar section of a modification. Fig. 3 is a detail of acombination permeable barrier and valve used in said modification.

The end of a transmission tube 1, constituting a part. of thedespatch'systcm, has been shown in both forms of the device providedwith a terminal 2; the tube'l. being inserted into the neck of theterminal and fixedly secured therein in a well known manner; the jointof course preferably being air tight. The terminal casing is ex tendedlaterally to afford a passage 4: through. which compressed air may beelelivered to a cavity 5 surrounding the eX- .tremityof the tube 1; thelatter preferably being perforated at intervals therearound, as at 6.The source'of compressed air may be a pipe 7, screwed into an extension8 of the terminal casing. said extension being recessed as at 9,toprovide a valve chamber in which is disposed a valve 10. The latter isadapted to seat against the lip 11 of an opening 12 which connects thechamber 9 with the passage l-previously referred to. The valve 10 may beof. any suitable construction and is mounted upon. a stem 13, the upperextremity of which projects through the wall of the terminal and isconnectedby means of a pin 14 with a short lever 15. A coiled spring 16normally urges valve 10 toward its closed position. The terminal. isprovided with a suitable orifice 17 through which carriers may beinserted into the tube 1, said orificebeing adapted to be closed by anormally open clapper valve 18. This valve,it should suffice to say, isof a well'lmown construction in common use in this art and is pivotallymounted upon a shaft 19; the pivoting ears 20 of the backing plateZl ofsaid valve further having a pin 22 extending transversely therethroughupon which is pi'votally mounted a lever 23. The forward extremity ofthis lever is provided with a handle 24 and the rear extremity thereofis provided with a hook 25 which is adapted for engagement with theforward end of the lever 15. The latter is mounted upon a pin 26 whichextends through lugs 27, said lugs projecting upwardly from the surfaceof the terminal casing adjacent the stem 13. A coiled spring 7 dicatedby dotted lines in said figure.

28 in a recess 29 in the lever 23 provides for a proper and effectiveclosure of the clapper valve when said lever 23 is in the position inwhichit is shown in full lines in Fig. 1. A spiraled spring 29 disposedaround the shaft 19 and suitably connected as at 30 to one of the ears20 exerts a tendency to swing the clapper valve into its open position,in-

The action of the spring 29 however, is resisted by a latch 31 pivotallymounted as at 32 between ears 33 of an auxiliary casing 34; said latchoperatively engaging a hook 35 which depends from the under side of thelever 23. Latch 31 is held normally in its operative or latchingposition by means of a light spring 36 and thelower extremity of thislatch lever may be provided, if desired, with a set-screw 37, thefunction of which will be hereinafter referred to.

The supplementary casing is' preferablypiston 42 which correspondinglyrides in a cylindrical recess 43 within a cap 44. This cap is furtherpreferably adapted to be readily separated from the supplementary casing34 upon the outer face of which it is mounted, so as to afford access tothe respective pistons.

A valve 45 of somewhat peculiar construction is pivotally connected asat 46 to the outer end of the cap 44, suitable means, such for exampleas a leather washer 47 (sethe latter in a well known manner.

one and indeed in practice it is desirable to I reduce it, when thepistons are so disposed, to the smallest dimensions possible. A needlevalve 50, or the like, provides means for closing the aperture 49 thedesired amount; this valve being mounted in an apertured cup 51 whichsecured upon the outer side of the valve 45. lhis cup is also preferablymade readily separable from said valve so as to permit of theperforation 49 being cleaned out to free it from the accumulation ofdust which is deposited therein by the currents of air which traversethe same; and also to permit of cleaning the needle point of the valve50. This latter may, if desired, be provided with a lock nut 52 so thatwhen it hasonce been set to determine the rate of flow of air throughthe perforation 49 it will not be disturbed when the cup 49 is removedfor cleaning purposes.

The pistons 39 and 42 may be provided with leather cups 39 and 42 in awell. known manner to insure air tight closures therearound; and thebacking plate 53 of the cupor disk 39 is preferably provided with a bossor extension 54 to permit either said extension or, as in the presentcase, the riveted end 55 of the piston stem 41 to engage the head of theset-screw 37. Means are provided for admitting pressure iiuid to thechamber 40 and such means, in the present instance, consists of a smalltube or pipe 56 which connects a preferably enlarged portion of thechamber 40 with the passage 4. I also prefer, in some cases, to

provide means for throttling the flow of pressure fluid from the passage4 into the chamber 5; any suitable device being employed for thispurpose. In the present instance a throttle valve 57 has been utilized,the function of which will be hereinafter referred to.

The operation of the device is as follows:

After a carrier has been inserted into the terminal opening 17, thevalve 18 is closed by means of the handle 24 and is automaticallylatched by the latching part 31. The last portion of-the movement of thevalve lever 23 brings the hook 25 at the rear extremity thereof intoengagement with the lever15 which rotates about its axis and therebyeffects the opening of the normally closed valve 10. It may here benoted that the extremities of the pin 14 which connect the lever 15 withthe valve stem 13 preferably ride in slots 58 in the bifurcated end ofthis valve stem. The valve 10 normally does not open until the clappervalve 18 has been seated so that there is practically no tendency towaste the pressure fluid; the latter passing through the opening 12,passage 4 and chamber 5, into the upper end of the transmission tube'andpropelling the carrier through While the compressed. air is passing intothe chamber some of it will also pass through the tube 56 to the chamber40. Herev it will, of

course, exert pressure against the opposed walls of the two pistons butsince the piston 39 is materially larger than the other, the piston rodor stem 41 will move toward the left as viewed in Fig. 1; its movementbeing impeded by the creation of a vacuum or partial vacuum in front ofthe piston 42 but to the left thereof as viewed in- Fig. 1. Air,however, slowly seeps in through the throttled aperture 49 and hencepermits the pistons to continue their movement toward the left; thespeed of this movement being governed by the position of the valve 50.The

advance of the pistons toward the left finally brings the head 55 of thepiston stem into engagement with the head of the set-screw 37 andimmediately thereafter trips the latch 31 releasing the lever 23 andpermitting the latter, together with the clapper valve attached thereto,to swing open under the influence of the spring 29. This tripping of thelatch is so timed as to. insure the delivery of the carrier to theterminal at the other end of r the line and the set-screw 37 permits ofthe regulation of this period to an extreme nicety. As the clapper valve18 is thus swung open, the lever 15 is substantially simultaneouslyreleased and the spring 16 closes the valve 10 preventing a furtherefliux of pressure fluid through the passage The latter being now incommunication with the atmosnormal positions and this action ispermitted by reason of the pivotal mounting of the valve which swingsupwardly and permits the confined air to freely escape around saidvalve; the latter thereafter being immediately returned to its closedposition. When the transmission line is of'considerable length there ispractically no necessity for providing a throttle 5'7 since .suflicientpressure in the chamber 40 to actuate the pistons in the mannerabove'described will be practically invariably developed under suchconditions. here, however, the transmission line is very short, it isadvisable to provide some means for insuring the development ofadequatepressure in said chamber 40 and the throttle 57 convenientlyprovides such means since it prevents the too free flow of air into thechamber 5 from the passage 4 and insures an adequate flow of air fromsaid passage 4 to the chamber 40. By reason of the fact that thepressure of air, upon the pervious barrier or valve 45 can never exceedthat of the atmosphere, the flow of air through the perforation 49 canbe regulated or determined to an extreme nicety and this despite thefact that the operating pressure in the line' may be relatively high.Furthermore, owing to this limited pressure upon the barrier in questionthe speed of the current of air flowing through the perforations thereincan never exceed a determined amount which not only permits of a moreaccurate regulation of the timing mechanism but further tends to reducethe tendency experienced in practice for the dust entrained in'the airto gradually clog or choke up the perforation. If desired, also, apledget 59 of absorbent cotton, gauze, vor the like, may be disposedwithin the-cavity in the cup 49 which will, of course, tend to filterthe air and thereby reduce this clogging action.

In the form of device shown in Fig. 2 the construction is practicallyidentical in all respects with that employed in the form of device shownin Fig. 1 except thatin this case the supplementary casing 34 has but asingle piston 60. The piston rod 61 of the latter rides in the bearing62 which forms a part of the front wall of the cylinder 68 within whichthe piston travels. Air is admitted to the space between this'wall andthe piston by means of a tube 56, as in the preceding case. The outerextremity, of the piston rod, in the present instance, carries a disheddisk 64 around which isdisposed a collapsible or folding wall 65 notdissimilar to the wall of a Chinese lantern.

This wall may be made of treated linen or some other suitable'toughmaterial which naturally is, or which has been treated to be,substantially impervious to air. When in its outermost position, theouter face of the disk 64 is received into an aperture in an annulus 66to the outer side of which is hinged a valve 67 of porous materialthrough which air may pass or seep slowly. In other words, this valvemay be such a permeable barrier as is described by the said George H.Woodman inhis patent above referred to. I prefer, however, to providemeans for regulating the flow of air through this barrier and one verysimple form of such means consists in merely lightly gumming a sheet 68of non-porous paper to the outer face of this flap or valve 67. Ifdesired, this sheet may be slit as at 69 (see Fig. 3) and any desiredportion thereof may be torn away as at 70, without disturbing theremainder, to expose the surface of the perwvious barrier 67. Oneadvantage. of this construction resides in'the fact that as the pores orminute apertures in this material become clogged up it is merelynecessary to l-l-l remove a further portion of the covering sheet 68 soas to regain the desired flow of air into the space within the foldingwalls 65. The annulus 66 may be retained in place by means of anapertured cap 71 and screws 2, or the like, said cap, of course beingreadily removable to permit of access to the valve 67. A light spring 73may be secured to the inner side of the cap 71; the free end of saidspring bearing against the outer side of the valve to insure a promptclosure thereof after it has been swung outwardly to permit of the airin front of the disk 64: being expelled. The rear flange 7a of this diskis adapted for engagement with the point of a set screw 75, said screwbeing carried by an arm of the latch 76, substantially the same as inthe preceding case. This form of the device operates in much the samefashion as does that previously described the only material differencesbeing that the outer or smaller piston in the present case has beenreplaced by the structure provided with folding walls and that theprevious barrier in this instance is made of porous material or ofmaterial. having pores made therein and further, that the means forregulating the flow of air through the said barrier is of a differenttype from that previously discussed. The closure of the valve 18 effectsan opening of the valve 10 whereupon air rushes through the tube intothe space in front of the piston impelling the latter rearwardly andthereby creating a partial vacuum in the space betweenthe flap or valve67 and the disk 64:; the slow seepage of air through the pores of thevalve 67 pcrmitting'the piston to continue its travel to the left, asviewed in Fig. 2, at a relatively slow rate of speed until the flange 74unlatches the lever 23 byits engagement with the screw 75. Thereafterthe valve 10 is closed as previously described and the air confinedbetween the piston and the front wall of its cylinder is driven outagain through the tube 56 by reason of the action of the spring 76'which bears against saidwall and'against the disk 64 and which performssubstantially the same function as does the spring 58 previouslyreferred to. The outward movementof the disk 6% expels the air which hadpreviously seeped in through the pervious barrier by forcibly raisingsaid barrier or valve from its seat; the latter thereupon beingre-seated by a spring 78. Indeed, in many cases this latter element isscarcely necessary since the mere tendency to form a' vacuum 7 betweenthe valve 67 and the disk 64 will cause said valve to seat itselffirmly.

In general, the provision of means for opposing the movementof a timingelement in a mechanism of the character above described, by fluidpressure of a sign opposite to that which tends to move said ele ment,is believed to be broadly new; and the advantages'of sucha provisionhave been above pointed out at length.

Having thus described my invention, what I claim is: i

1. Pneumatic transmission apparatus comprising a'member having a biasfor a determined position with respect to other parts of said apparatus,and time element mechanism for controlling the return of said memher tosaid position after displacement therefrom, said mechanism including aninstrumentality, displaceable in a given direction by fluid pressure,means to supply said fluid pressure, and cooperating vacuum formingineans'having a vacuum forming chamber therein provided with auxiliarymeans to admit pressure fluid at a determinedrate to said chamber andco-acting with saidinstrumentality when the latter is moved in a givendirection, for retarding said movement to time the return of saidmember, said mechanism also including means to hold said member againstreturn to said position thereof until said instrumentality has reached adetermined point in its path of travel in said given direction.

2. Pneumatic transmission apparatus comprising a valve having a bias fora determine dposition with respect to other parts of said apparatus, andtime element mechanism.

for controlling the return of said valve to said position afterdisplacement therefrom,

said mechanism including an instrumentality displacement in a givendirection by fluid pressure means to supply said fluid pressure, andcooperative vacuum forming means havinga vacuum forming chamber thereinprovided with auxiliary means to admit pressure fluid at a determinedrate to said chamber and co-acting with said instrumentality, when thelatter is moved in 'a given direction, for retarding such movement totime the return of said valve, said mechanism also including means tohold said valve against return to said position thereof until saidinstrumentality has reached a determined'point in its path of travel insaid given direction.

3. A; transmission system comprising a source of compressed air, amember having a bias for a determined position, and timeelement'mechanism for controlling the return of saidmember to saidposition after displacement therefrom, said mechanism including aninstrumentalitv displaceable in a given direction by compressed air fromsaid source of the same and cooperating vacuum forming means co-actingwith said instrunientality when the latter is moved in a givendirection, for retarding such movement to properly time the same. 7

4.13. transmission system comprising a source of compressed air, a valvehaving a master a determined position, and time element mechanism forcontrolling the return of said member to said position afterdisplacement therefrom, said mechanism including a latch and aninstrumentality for actuating said latch, said instrumentality beingadapted for displacement by compressed air from said source of the same,and cooperating vacuum forming means co-acting with said instrumentalitywhen the latter is moved in a given directiomfor retarding such movementto properly time the same.

5. In pneumatic despatch tube apparatus, a transmission tube and meansfor establishing a propulsive fiuid pressure in said tube, incombination with a cooperating time element mechanism for saidapparatus, said mechanism comprising a part movable by said fluidpressure and means for retarding, by an opposing fluid pressure ofopposite sign, a movement of said part, and means controlled by saidmechanism and co-acting with a part of said fluid pressure establishingmeans to disestablish said propulsive fluid pressure after said movablepart has traveled a determined distancewhil'e subjected to the action ofsaid retarding means.

6. A transmission system comprising a holding said valve in a determinedposition,

and time element means for actuating said holding means, said timeelement means including an instrumentality, movable by compressed airfrom said source or" the same, and cooperating vacuum forming meansco-acting with said instrumentality, when the latter is moved by saidcompressed air insaid given direction, for impeding such movement.

In testimony whereof I have afiiXed my signature, in the presence of twowitnesses.

CHARLES P. HIDDE Witnesses:

B. J. SMITH, Isaac KnAFsUR.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G,

